How can i enable composite node in python?
Set active node

Similarly to Set active image node with python

In the python console 

C = bpy.context
D = bpy.data

&gt;&gt;&gt; node = C.scene.node_tree.nodes['Composite']
&gt;&gt;&gt; node.select = True
&gt;&gt;&gt; C.scene.node_tree.nodes.active = node
&gt;&gt;&gt;